Abstract Antiretroviral treatment (ART) is the single most effective clinical intervention in the fight against HIV. However, in Uganda only 56% of people living with HIV were virally suppressed in 2017 with significant disparities between men and women, suggesting problems with implementation. While gender norms are a known driver of HIV disparities in sub-Saharan Africa, and patient-provider relationships are a key factor in HIV care engagement, little research has focused on the role that gender norms have in shaping the equitable provision of treatment and quality of ART counseling. The proposed training plan in this Mentored Research Scientist Development Award (K01) application will provide the knowledge and skills needed for the principal investigator, Katelyn M. Sileo, PhD, MPH, to develop a program of research to investigate and address these issues. The overall research objective is to develop and pilot test an implementation strategy to increase providers' capacity to provide equitable and gender-tailored treatment and counseling to HIV-infected men and women. Delivered to HIV providers, this 4-session group training integrates a gender transformative approach with adapted evidence-based strategies to reduce biases and increase gender equitable attitudes. The Consolidated Framework for Implementation Science Research (CFIR) will be used to guide a comprehensive needs assessment to inform the development of the implementation strategy, including qualitative data collected from clinic staff and leadership, patients, and community members. The implementation strategy will be assessed through a quasi-experimental delayed implementation design. Two clinics in Luwero and Wakiso District will be randomly assigned to either the Training Only (4 group sessions) or Training+ (4 group sessions plus additional maintenance sessions) conditions, with cross-over in 6-month intervals. The pilot trial will assess the implementation strategy's effectiveness by comparing changes in provider (N=30-36) (gender awareness and equitable attitudes) and patient (N=240) outcomes (quality of care, satisfaction, clinic attendance, ART adherence, viral load) across Training, Training+, and Usual Care through 18-months. The trial will also qualitatively explore CFIR barriers and facilitators to implementation and future adoption. This research project paired with coursework, workshops, academic conferences, one-on-one mentorship, and manuscript and grant-writing will target the following three training aims: (1) Develop expertise in the field of implementation science; (2) Develop expertise in gender theory and gender transformative health interventions; (3) Gain mastery of advanced statistical methods in the evaluation of implementation science research designs. Dr. Sileo will be mentored by an interdisciplinary team of world-renowned experts in HIV, implementation science, and gender ideologies. This K01 project will develop Dr. Sileo into an independent scientist specializing in the use of implementation science to reduce gender disparities in HIV outcomes.